“It’s very kind of you, I’m sure, Mrs. Dillon, to be taking all this trouble for me, that isn’t fit for duty to-night no more than your baby there. I’m very grateful that you will have an eye to this poor thing, for my sick headache just uses me up, and the doctor is very particular about her medicine. If you’d only take charge now while I catch a little nap, it would be a charity to more than one; but do be particular about the medicine.” Mary Margaret was seized with an unaccountable shudder, but she answered quite naturally, “Sure and I’ll do me best, marm.” “That’s a good soul; don’t forget the medicine, the directions are all on the bottles, and—and——” The voice was husky and unnatural, and all around her mouth settled a strange pallor, as if the sickness of which she complained had seized with new force upon her. “I’ll do my best,” repeated Mary Margaret, and she sat down upon the foot of the poor young creature’s bed like one who had resolved to guard it well. The nurse went half-way to her chair in the corner, and turned back with her face from the light. “In fifteen minutes it will be time to give her first dose,” she said, still huskily, and with an effort; “a teaspoonful, don’t forget.” “I’ll not forget, will I, me purty darlint?” answered Mary Margaret, folding the two pale hands of the invalid between her palms, and gazing upon her with kindly mournfulness. The nurse stumbled back to her corner as if worn out with her headache, and sat brooding there, sometimes with her eyes closed, sometimes with that basilisk glance peering out from above her folded arms. She reminded you of a rattlesnake watching amid its own coils. Mary Margaret caught these glances once or twice without appearing to regard them, but they kept her intellect upon the alert, and without knowing exactly what she was to guard against, the good woman felt that harm was around her, and that the evil thing must find her watching. A slight change in her position threw the light directly across the chair upon which the cups and vials used about the sick had been placed, and where she had left her basin of weak tea. Without having consciously made the discovery, Mary Margaret became aware that the only vial which stood upon the chair had been moved, and that its contents, a pale wine color, had become white as water. Still the vial was the same, and as she bent over softly to read the label, that was also unchanged, a “teaspoonful every hour.” This was what she read and had seen before while searching for drink among the empty cups. Why was this? For what object had the contents of that vial been changed? Who _could_ have done it but the nurse, and why _had_ she done it? Then Mary Margaret began to ponder over the change in nurse Kelly’s manner—the sudden favor into which she had fallen, and an unaccountable antipathy to give the medicine in that bottle seized upon her.